Arrow shaft

ABSTRACT

An arrow shaft composed of a non-elastic fiber and a low elastic fiber and a method for manufacturing the same are disclosed. The method comprises the steps of spreading an elastic sheet such as pre-impregnated or prepreged carbon or glass fiber, adhering a non-elastic or low elastic fiber, preferably a prepreged pre-impregnated natural, synthetic, or glass fiber onto the elastic sheet, winding them onto a mandrel, and carrying out tapping, heat treating/cooling, releasing, and polishing processes.

RELATED APPLICATION

[0001] The present invention is a divisional application of U.S. patent application Ser. No. 09/978,873, filed Oct. 16, 2001, which is pending.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates to a method for manufacturing an archery arrow, and more particularly, to an arrow shaft composed of a non-elastic fiber and a low elastic fiber, and a method for manufacturing the same.

[0004] 1. Background of the Related Art

[0005] Generally, a conventional archery arrow comprises, as shown in FIG. 3, a hollow arrow shaft, an arrow head fitted into a front end of the arrow shaft, a number of vanes attached to an outer periphery of a rear end of the arrow shaft, and a notch fitted into the rear end, the arrow shaft being a major part among the above components.

[0006] Several methods and materials for manufacturing the arrow shaft have been proposed. A typical example of arrow shaft manufacturing methods comprises the steps of: cutting; layering and winding; tapping; heat treating and cooling; releasing; and polishing.

[0007] The above method for manufacturing the arrow shaft includes several disadvantages as follows:

[0008] 1) To put a constant spin on the arrow, after carbon or glass fiber is layered and formed on a mandrel, and then the arrow shaft is ground to have a wanted diameter and spin. However the arrow shaft is accurately ground, a grinding error may be happened. Furthermore, at the first stage of grinding the material, the damage of the material is a factor of reducing the strength of the arrow shaft. There is another drawback of deteriorating the arrow shaft in that the partial wear is happened on the arrow shaft, and thus the linearity of the arrow shaft is lost.

[0009] 2) Since a polishing process is performed after previously aligning the linearity of the arrow shaft prior to polishing the arrow shaft, the linearity of the arrow shaft is lost, thereby increasing the percent defective of the arrow shaft.

[0010] 3) Since the material (i.e., carbon fiber or glass fiber) is layered at larger amount than that of the spin in view of the grinding amount, the cost of the article is increased. In addition, there is another drawback that since the surface of the arrow shaft is damaged, it is impossible to use the arrow shaft during a long time.

[0011] 4) After the spin and diameter of the arrow shaft are set, the weight of the arrow shaft is automatically determined due to the elasticity and specific gravity. Therefore, it is impossible to change the weight of the arrow shaft. In particular, after the grinding process, it is impossible to set the weight of the arrow shaft to a desired weight depending upon the specification.

[0012] 5) According to the typical method, the strength of the arrow shaft is necessarily reduced due to the grinding of the arrow shaft. In addition, since the arrow shaft is painted or transferred or is designed by attaching a sticker on the peripheral surface in order to camouflage the arrow shaft, an unnecessary process has to added, thereby causing reduced productivity and increased cost.

[0013] 6) If the transferring process is carried out, recessed portions are happened on the surface of the arrow shaft due to the variations of transferred thickness. During a long-range usage, the recessed portions will be easily worn, and the transferred portions will be easily detached from the surface of the arrow shaft.

[0014] 7) If the arrow shaft manufactured by the typical method is damaged, a sharpen portion will be exposed since the material has a mono-directional elasticity. Such a sharpen portion may can inflict a fatal injury to a human body.

SUMMARY OF THE INVENTION

[0015] Accordingly, the present invention is directed to a method of manufacturing an arrow shaft that substantially obviates one or more problems due to limitations and disadvantages of the related art.

[0016] An object of the present invention is to provide an arrow shaft and a method for manufacturing the same, wherein a proper amount of an elastic sheet such as carbon or glass fiber proper that determines a spin of the arrow shaft is calculated to obtain a proper spin, and a proper amount of the elastic sheet is layered on a mandrel; and a non-elastic fiber or a low elastic fiber that has no effect on the spin is layered on a top of the elastic sheet.

[0017] Other object of the present invention is to provide an arrow shaft and a method for manufacturing the same, wherein a non-elastic fiber is ground to maintain the initial linearity of the arrow shaft.

[0018] Another object of the present invention is to provide an arrow shaft and a method for manufacturing the same, wherein a spin of the arrow shaft can be constantly maintained.

[0019] Still another object of the present invention is to provide an arrow shaft and a method for manufacturing the same, wherein the weight of the arrow shaft can be adjusted by controlling the grinding amount of a non-elastic fiber or a low elastic fiber.

[0020] Further still another object of the present invention is to provide an arrow shaft and a method for manufacturing the same, wherein a desired design is printed on a surface of the arrow shaft using a printing and transferring method.

[0021] Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objectives and other advantages of the invention may be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.

[0022] To achieve the object and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, there is provided a method of manufacturing an arrow shaft by layering and winding an elastic sheet around a peripheral surface of a mandrel, the method comprising the steps of: when the elastic sheet is layered on the peripheral surface of the mandrel, layering a non-elastic sheet on an outermost surface of the elastic sheet; and winding the elastic sheet around the mandrel together with the non-elastic sheet.

[0023] According to another aspect of the present invention, there is provided an arrow shaft made of an elastic sheet such as carbon or glass fiber, the arrow shaft comprising: a non-elastic sheet adhered on an peripheral surface of the elastic sheet.

[0024] The non-elastic sheet comprises a natural fiber or cotton, and a chemical fiber.

[0025] It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the principle of the invention. In the drawings:

[0027]FIG. 1 is a schematic view illustrating a process of manufacturing an arrow shaft according to one preferred embodiment of the present invention, in which sheets are adhered onto an external circumference of a mandrel.

[0028]FIG. 2 is a cross sectional view illustrating an arrow shaft manufactured by the method of the present invention.

[0029]FIG. 3 is a perspective view illustrating the construction of a typical archery arrow.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0030] Reference will now be made in detail to the preferred embodiment of the present invention, an example of which is illustrated in the accompanying drawings.

[0031] The method for manufacturing an arrow shaft according to the present invention comprises the steps of spreading an elastic sheet such as pre-impregnated or prepreged carbon or glass fiber, adhering a non-elastic or low elastic fiber, preferably a pre-impregnated or prepreged natural, synthetic, or glass fiber onto the elastic sheet, winding them onto a mandrel, and carrying out tapping, heat treating/cooling, releasing, and polishing processes.

[0032]FIG. 1 shows a process of winding the sheets onto the mandrel, the process being a major process of the present invention. Referring to FIG. 1, according to the method of the present invention, after a first elastic sheet 102, a second elastic sheet 104, and a non-elastic fiber sheet 106 are cut to have a desired length, respectively, the sheets are prepregs or pre-impregnated and then are wound onto a surface of the mandrel 100.

[0033] The first elastic sheet 102 and second elastic sheet 104 are made of elastic material. Preferably, the first and second elastic sheets are made of a sheet made of carbon or glass fiber. One sheet made of carbon or glass fiber may be used, or a sheet of which the carbon fiber sheet and the glass fiber sheet are layered may be used. The non-elastic fiber sheet 106 is referred to a fibroid material, in particular, a natural fiber or cotton, or a chemical fiber. The non-elastic fiber may be is painted or transferred with various designs to be under the disguise of the arrow shaft.

[0034] The arrow shaft 200 prepared by the above winding process includes, as shown in FIG. 2, the first elastic sheet 102 formed in a cylindrical shape, and the second elastic sheet 104 adhered onto the external circumference of the first elastic sheet 102. The non-elastic fiber sheet 106, preferably a painted fiber, is adhered onto the external circumference of the second elastic 104. The arrow shaft 200 constructed as described above can address the drawbacks contained in the typical arrow shaft. In particular, the present invention has advantages of controlling the weight of the arrow shaft and constantly maintaining the initial linearity thereof.

[0035] One preferred embodiment of the present invention will now be explained, but the present invention is not limited to the embodiment.

[0036] Embodiment

[0037] After a releasing agent is applied on the entire surface of an external circumference of a mandrel in order to easily carry out a releasing process (i.e., a process of releasing an article from the mandrel), an adhesive is applied on the releasing agent. A carbon sheet, a glass fiber sheet, and a natural fiber sheet with various designs printed are cut to have a desired length, respectively. At that time, the carbon sheet, the glass fiber sheet, and the natural fiber sheet are pre-impregnated (prepregs).

[0038] Next, as shown in FIG. 1, the glass fiber sheet is adhered on the carbon sheet, and then the natural fiber sheet is adhered on the glass fiber. After an end of the carbon sheet is adhered on the surface of the mandrel, the sheets are wound around the mandrel by a rolling unit (not shown), this process being hereinafter referred to a rolling process.

[0039] A film is wound around the entire surface of the resultant executed by the rolling process, preferably the natural fiber sheet, using a tapping unit (not shown), this process being hereinafter referred to a tapping process. Preferably, polyethylene telephthalate resin (PET) film or oriented polypropylene(OPP) film is used as the above film. The tapping process is executed immediately prior to the shape of the article executed by the rolling process, so that air existed between each sheet layer may be discharged outwardly and an interior layering degree of the article may be increased.

[0040] And then, the mandrel is heated with gradually varying a temperature during 4 hours, preferably under a temperature of 80 to 150° C. during 1 to 4 hours, thereby shaping sheet layers wound around the mandrel. After that, the shaped article is released from the mandrel.

[0041] Finally, after both ends of the article released from the mandrel is cut to have a length of approximately 825 mm, the film is released from the surface of the natural fiber sheet. The method of manufacturing the arrow shaft is completed by carrying out centerless polishing on the surface of the natural fiber sheet.

[0042] The method of manufacturing the arrow shaft according to the preferred embodiment of the present invention has some advantages as follows:

[0043] A proper amount of the elastic material that determines the spin of the arrow shaft is previously calculated to obtain a proper spin, and a non-elastic fiber that has no effect on the spin is layered on a top of the elastic material, so that the arrow shaft having no spin variations can be provided.

[0044] Since the non-elastic material is ground, the weight of the arrow shaft can be adjusted according to the grinding amount. In addition, the surface of the arrow shaft is smoothed, and thus the arrow shaft is soft to the touch. In particular, since the eccentricity and the initial linearity of the arrow shaft can be maintained.

[0045] The present invention can camouflage the arrow shaft by painting the non-elastic fiber to have various designs. It can address drawbacks contained in the typical method that due to the transferring process the productivity is decreased and the cost is increased.

[0046] If the arrow shaft manufactured by the present invention is damaged, since the fiber encloses the damaged portion, a sharpen portion is not exposed, thereby protecting a human body.

[0047] The present invention grinds not an expensive elastic material, but an inexpensive non-elastic fiber, thereby reducing the cost of the arrow shaft and improving the productivity thereof.

[0048] The forgoing embodiment is merely exemplary and is not to be construed as limiting the present invention. The present teachings can be readily applied to other types of apparatuses. The description of the present invention is intended to be illustrative, and not to limit the scope of the claims. Many alternatives, modifications, and variations will be apparent to those skilled in the art. 

What is claimed is:
 1. An arrow shaft manufactured by a method claiming: layering and winding an elastic sheet around a peripheral surface of a mandrel; when the elastic sheet is layered on the peripheral surface of the mandrel, layering a non-elastic sheet on an outermost surface of the elastic sheet; and winding the elastic sheet around the mandrel together with the non-elastic sheet.
 2. An arrow shaft according to claim 1, wherein the non-elastic sheet is a sheet made of a fibroid material.
 3. An arrow shaft according to claim 2, wherein the non-elastic sheet comprises a natural fiber, cotton, and a chemical fiber.
 4. An arrow shaft according to claim 1, wherein the non-elastic sheet is painted to have various designs.
 5. An arrow shaft made of an elastic sheet, the arrow shaft comprising: a non-elastic sheet adhered on an peripheral surface of the elastic sheet.
 6. An arrow shaft as claimed in claim 5, wherein the non-elastic sheet comprises a natural fiber, cotton, and a chemical fiber.
 7. An arrow shaft as claimed in claim 5, wherein the elastic sheet carbon or glass fiber. 